CN1142792A

CN1142792A - Apparatus for manufacturing steering rack bars

Info

Publication number: CN1142792A
Application number: CN94194932A
Authority: CN
Inventors: A·E·毕晓; L·J·麦连
Original assignee: AE Bishop and Associates Pty Ltd
Current assignee: AE Bishop and Associates Pty Ltd
Priority date: 1993-12-16
Filing date: 1994-12-16
Publication date: 1997-02-12
Anticipated expiration: 2014-12-16
Also published as: AUPM302693A0; CA2177834A1; WO1995016529A1; US5862701A; KR100287224B1; ES2143040T3; EP0738191A1; JPH09506550A; EP0738191A4; KR960706380A; EP0738191B1; DE69423518D1; CN1058433C; JP3351793B2; BR9408222A; CA2177834C; DE69423518T2

Abstract

A forging die for forming a steering rack portion having teeth and two longitudinally extending guide faces from a blank. The die comprising first (18) and second (19) die members and four forming elements (52, 53, 54, 55) to converge on the blank. The first forming element (52) being on the second die member (19) for forming the teeth, the second (53) and third (54) forming elements being on the first die member (18) for forming the guide faces. The fourth forming element (55) slidable relative to the first die member (18) for forming a surface of the portion and connected to a first bias means (83, 84) allowing movement of the fourth forming element (55) during forging. The die having opposed first and second grippers holding the blank during forging, the first gripper (23) connected to a second bias means (25, 36) and slidable relative to said first die member (18) and the second gripper (24) connected to a third bias means (26, 28) and slidable relative to said second die member (19), with the first bias means mechanically separated from the second bias means.

Description

Be used to make the device of steering rack

Technical field

The present invention relates to a kind of steering rack and manufacturing thereof of automobile.Background technology

Most steering rack is made with the column rod iron, and from the end cutting teeth near this column rod iron, the band toothed portion is approximately 1/4th of rod iron length.The shortcoming of this manufacturing tooth bar technology is at United States Patent (USP) the 4th, 715,210 and 4,571, be described in No. 982, these two patents have been described respectively by forge the method and apparatus of making steering rack in the multicomponent mould of a kind of so-called " Y " pattern tool, in this Y pattern tool, the forming element of mould comes together towards rack central line, to guarantee " burr " minimum of forming pressure maximum, generation.This technology is specially adapted to make the tooth bar that the band toothed portion has the unique transverse shape that is similar to capitalization " Y ", and its great advantage is at United States Patent (USP) the 4th, 116, the existing description in No. 085.

With United States Patent (USP) the 4th, 571, the tooth bar that 982 devices of being put down in writing are made, its bending and fatigue strength are better than the tooth bar with the manufacturing of same diameter column rod blank, and as United States Patent (USP) the 3rd, in 753,378 disclosed these forging processes, no matter be that the profile of tooth or the toothed region of variable gear ratio of constant ratio can obtain.Therefore the change curve of variable gear ratio, can not accurately broach or grinding along the axial smooth variation of tooth bar, and except forging, other method for example can not be produced economically with chemistry or Electrical Discharge Machine processing method.

Since nineteen eighty-three, tooth bar is to produce with United States Patent (USP) 4,571,982 described " warm forging " technology always.The characteristics of mould therefor are that the volume of mold cavity volume and blank closely mates, so that " burr " minimum that produces.Though declaring the benefit that obtains is to have improved fatigue and bending strength, product good straightness degree around the main shaft, reduced producing cost and can produce the profile of tooth of variable gear ratio,, produce economic its shortcoming of proof and concentrate in the existing Y type Mould design.

The major defect of existing Y pattern tool is can not control independently to forge and the clamping load.In the mould of this prior art, upper modules (load is forged in control) and upper clamp (control clamping load) all are fixed on the plate, and, borrow two springs preload vertically downward.This plate can be on upper deck vertically slides, so upper modules and upper clamp can not be carried out self-movement.Upper modules is used for holding in the tooth bar Y type cross section rod form metal to upper process, and finds in the reality that in order to adapt to the diameter tolerance of tooth bar base, upper modules also has variation (but very slight) to a certain degree.The plate that the result causes being equipped with upper modules and upper clamp also needs variation to a certain degree, thus, causes the changeability of clamping load.

In addition, onboard the unequal loading meeting of distributing causes the support side warpage vertically upward of facing the relative upper clamp in plate side that connects tooth bar band toothed portion, and the tendency that the upper and lower anchor clamps are pried open is arranged.Like this, cause the chucking power loss, cause that by way of parenthesis the pressure of mould itself is impaired, make filling (fill) quality of tooth become bad then, and metal base is extruded between the anchor clamps vertically.The warpage that plate makes progress relatively can further cause being distributed in the axial compressive force inequality in the die cavity, the size that often needs repeatedly to adjust upper modules repeatedly could obtain satisfied tooth filling and Y type cross section, this process must be carried out after each conversion machining tool, the result, both time-consuming, be not suitable for the environment of the production in enormous quantities that needs rapid conversion machining tool again.

Further, the tooth bar glacing flatness that the inhomogeneous warpage of above-mentioned plate can cause forging reduces, and shows the transition region bending between band toothed portion and the stylolitic part.

Other shortcoming of the existing design of Y pattern tool is to utilize mechanical type spring control forging force and chucking power.As United States Patent (USP) 4,571,982 described coil springs are difficult to assembling, owing to this reason, use mechanical beam type spring (beam spring) so far in producing Y pattern tool always.Yet, the spring preload force of above-mentioned this mechanical type spring (no matter being spiral or the beam type spring) all is difficult for changing, but, therefore make production process mutability occur also because the loss of mechanical preload force increases these spring fatigue failure likelihoods because of wearing and tearing need to change in the use.And the tooth bar of different size needs different maximum load on spring and/or spring rate.And these parameters also are malleable not in production environment.

The objective of the invention is to overcome the shortcoming of Y pattern tool in the prior art, and provide a kind of be used for making have United States Patent (USP) 4,571, the steel-tooth bar of the shape described in 982.Key character of the present invention provides the separately control to chucking power, forging force and pressure.This clamping function with forge separate of function, can make every toothed rack optimization along with the improvement of tooth filling and the straight raising of tooth bar.Further, upper modules and upper and lower anchor clamps from mould when fully closed returning of present position can independently control and regularly so that discharge the forged rack that contacts with other mould, avoided the great destruction of tooth bar and misaligned.The present invention can also be under the situation of not removing mould, and making quick fine setting or resetting the forging parameter becomes possibility, thus, but the Fast transforms machining tool, and make described mould be applicable to mass-production environment.Summary of the invention

One aspect of the present invention provides a kind of mould, makes blank be processed into steering rack band toothed portion by forging with this mould.This band toothed portion has the spigot surface of toothed and at least two longitudinal extensions, described mould comprises first, second die component and by first, second, the element group that the 3rd and the 4th forming element is formed, these forming elements can be gathered on blank when blank is put into mould with relatively moving, first forming element is the part of second die component, and one of them mask has and the corresponding shape of described profile of tooth, the second and the 3rd forming element is the part of first die component, and the forming face that the spigot surface that is suitable for processing belt toothed portion longitudinal extension is arranged, the 4th forming element links to each other with first biasing device, between the second and the 3rd forming element, slide with respect to first die component, and be suitable for the processing belt toothed portion between two spigot surfaces and with the tooth facing surfaces, described first biasing device allows the 4th forming element to leave blank during forging under the load effect and moves, this mould also is included in during the forging the vertically grasping system of restriction blank, grasping system is included in first and second anchor clamps that the non-machined surface of blank applied during the forging positioned opposite of radial load, first anchor clamps link to each other with second biasing device, and can slide by relative first die component, second anchor clamps link to each other with the 3rd biasing device, and can slide by relative second die component, it is characterized in that first biasing device mechanically separates with second biasing device.

First, second and the 3rd biasing device be hydraulic actuator preferably.The 3rd and second biasing device also can fluid connection.Certainly, as another replacement form, the 3rd biasing device also can be a mechanical spring, and in this case, second biasing device and the 3rd biasing device do not need fluid connection.

What the moment of pressure effect and size were preferably controlled separately in a hydraulic actuator at least.Also the function that it is relatively moved as first and second die components can be controlled to any one or a plurality of hydraulic actuator.

At least one hydraulic actuator is preferably controlled by at least one Pressure relief valve.Also can on the liquid connector between at least one hydraulic actuator and its corresponding overflow valve, connect an accumulator.

Mould preferably also comprises the restraint device that is used for vertically limiting blank during forging, this restraint device is being rotatably mounted around the axis that is basically perpendicular to blank, and have a surface that is basically perpendicular to the blank longitudinal axis, and be clamped in by a clamping device at the mould period of contact on the fixed stop part of second die component.

Another aspect of the present invention, a kind of mould is provided, make blank be processed into steering rack band toothed portion with this mould by forging, this band toothed portion has the spigot surface of toothed and at least two longitudinal extensions, described mould comprises first, second die component and by first, second, the element group that the 3rd and the 4th forming element is formed, these forming elements can be gathered on blank when blank is put into mould with relatively moving, first forming element is the part of second die component, and one of them mask has and the corresponding shape of described profile of tooth, the second and the 3rd forming element is the part of first die component, and has a forming face of the spigot surface that is suitable for processing belt toothed portion longitudinal extension, the 4th forming element links to each other with first hydraulic actuator, can between the second and the 3rd forming element, slide with respect to first die component, and be suitable for the processing belt toothed portion between two spigot surfaces and with the tooth facing surfaces, first hydraulic actuator allows the 4th forming element to move down the cogging material and move in the load effect during forging, it is characterized in that, control for pressure effect moment and size in first hydraulic actuator.The detailed description of accompanying drawing

For understanding the present invention better, below with reference to accompanying drawing, by means of infinite example the embodiment that is used for putting into practice is described in detail.Wherein:

Fig. 1 is the tooth bar schematic diagram according to Mold Making of the present invention;

Fig. 2 is the tooth bar cross-sectional view on A-A plane among Fig. 1;

Fig. 3 is the skiagraph of the mould according to the present invention;

Fig. 4 is the mould sectional drawing on C-C plane among Fig. 3;

Fig. 5 is the D-D plane mould sectional drawing among Fig. 3;

Fig. 6,7 and 8 shows the different phase that forms tooth bar Y type part and tooth;

Fig. 9 shows the power that acts on the module and the relation between the pressure, and the two all is the function of mould aperture; And

Figure 10 a～c is the skiagraph that amplifies, it at length show guiding valve among Fig. 3 three disalignments to and the structure of position of rotation.

Figure 10 a～f is at the sectional drawing on E-E plane corresponding to corresponding spool among Figure 10 a～c.

The most preferred embodiment of invention

Fig. 1 shows the typical Y type tooth bar of making according to embodiments of the invention of being made up of band toothed portion 1 and stylolitic part 2.Usually, tooth bar end 3 is threaded, and is connected on ball-and-socket head and the drag link.In the type that another kind is of little use, drag link is fixed on the aforementioned tooth bar by means of the stud that has rubber bushing near the longitudinal direction of car position of center line, and purpose is that the column tooth bar of making has local expansion, is drilled with the hole and attacks threaded characteristic.Hereinafter the method that will narrate is applicable to that also the toothed portion of making these " off-centring " tooth bars (centre-take-off) and other type has the tooth bar of interchangeable shape of cross section, and above-mentioned interchangeable shape of cross section is to realize by respectively the profiled surface of module being made suitable shape.

Fig. 2 shows the section configuration of tooth bar Y type toothed portion.Circumference 13 is illustrated in the tooth bar stylolitic part 2 of this view.Relative a pair of spigot surface 5 and 4 is symmetrical arranged with respect to vertical axis 6, angle 7 between them is about 90 °, tooth 8 ends at angled end-face 9 and 10, obtains optimum utilization so that use to put the 12 circle 11 represented spaces, effective cross section that turn to inside pipe casing as the center of circle.The angled end-face of this tooth also is used for reducing the variation of breaking of the outer end of tooth.Stylolitic part 2 is the center to put 12 also.And select its diameter that its cross-sectional area is equated with the average cross-section area of band toothed portion 1 substantially.The bar 14 of Y type part is made the shape that tapering is arranged slightly, and its relative two sides form with the represented swallow-tail form in angle 15.

Fig. 3,4 and 5 shows an embodiment who is used to make the mould of aforementioned type tooth bar according to of the present invention, and this mould is installed on the forcing press (not shown) with movable platen 16 and stationary platen 17.

Described mould comprises and is separately fixed at upper mould member 18 on the

lower platen

16 and 17 and lower die member 19 on the forcing press, described the position that mould when tooth bar 20 is shaped fully is in complete closure in every width of cloth figure of Fig. 3,4 and 5 three views.Described mould is divided into two zones along the length of tooth bar, i.e. clamping zone 21 and shaped region 22 (Fig. 3).

When upper mould member 18 descends, at first engages as the several elements with the represented clamping zone 21 of sectional view among Fig. 5 with tooth bar base 20, then, several elements of shaped region 22 shown in Figure 4 are by the complete tooth portion of one-shot formation tooth bar.

Clamping zone 21 comprises upper clamp 23 and lower clamp 24, and each anchor clamps has one and engages the semi-circular groove of tooth bar base 20, and is loaded by

hydraulic cylinder

25 and 26 respectively.

Lower clamp 24 is fixed on the plunger 27, and with before tooth bar base 20 contacts, piston 28 is supplied with the effect that oil pressure is generally 2～3.5MPa, upwards promotes plunger 27 in upper clamp 23.When mould is opened, supply with the value of oil pressure and adjust by overflow valve 29, during clamping, this is supplied with oil pressure and is then adjusted by overflow valve 30.Moving downward by plunger 27 of lower clamp 24 limits with contacting of pad 31, and moving upward then limits with contacting of locating rack 49 (Fig. 3 and Fig. 5) by plunger 27.

Upper clamp 23 is fixed on the plunger 33, and with before tooth bar base 20 contacts, piston 36 is supplied with the oil pressure effect, promotes plunger 33 downwards in upper clamp 23.The moving upward to contact with bearing 34 by plunger 33 of upper clamp 23 limits, and moves downward then to limit with contacting of pad 35 by piston 36.

Pad 31 forms the adjusting device of lower clamp 24 strokes, is adjusted in the tooth bar degrees of offset at 43 places, plane thus, to adapt to the different designs scheme of tooth bar.Locating rack 49 control lower clamp 24 are with respect to the initial position of bottom toothed die 52.Pad 35 forms adjusting device, adjusts the stroke of upper clamp 23, to adapt to the different designs scheme of tooth bar.

Adjustable compactor

51 and 50 provides one to compensate after

anchor clamps

23,24 trimming device that size in vertical direction reduces respectively.

When mould period of contact, upper clamp 23 contacted with tooth bar base 20, as shown in Figure 3, the pressure that is provided that moves down because of piston 28 had been provided for the hydraulic cylinder 25 of interconnection and 26 pressure recruitment, and the area of piston 28 is less than the area of piston 36.The oil of being discharged by piston 28 overcomes moving of spring 38 by overflow valve 30 by means of the flap 37 of this valve and discharges from mouth 106.The outlet pressure of overflow valve 30, and the chucking power size that is produced by upper clamp 23 and lower clamp 24 that causes thus sets by the preload force of adjusting spring 38, and the setting of spring 38 preload force then is by the screw rod 41 that is locked at the appropriate location by locking nut 42 the moving of plunger 39 in the hole 40 of overflow valve 30 to be obtained.

Before mould arrived complete closure, when plunger 27 contacted with pad 31, lower clamp 24 arrived the bottom.On this point of forming period, piston 36 begins to move up with respect to upper mould member 18.The oil of discharging along with the motion of piston 36 is discharged by overflow valve 30 again.

Piston 28 and 36 area are done following selection, make the pressure that acts on these pistons identical, and the summation that makes piston 36 applied forces can be enough to overcome piston 28 applied forces and be used for shearing the needed power of skew of the tooth bar base 20 in the out-of-plane 43.

Because the response time that requires overflow valve 30 to make is extremely lacked (being opened for 7 milliseconds usually fully).The application can not use pilot valve control overflow valve, thereby overflow valve 30 must be the direct action type.Known in this area, this direct acting overflow valve 30 is influenced by unstability potentially, and is responsive especially to the pace of change of pressure.Therefore, accumulator 44 is set so that act on the speed of the pressure rising on the overflow valve 30 and is limited to acceptable limiting value, be generally 1400MPa/s.

Mould period of contact, check valve 45 stop the oil of discharging from

hydraulic cylinder

25 and 26 to flow into supply passageway 46.Begin closed moment at mould, close magnetic valve 47 and liquid flow is stopped and keeping closing closed state, open up to mould, and the tooth bar that has been shaped with the device for ejecting ejection till, this device for ejecting will be narrated hereinafter.When magnetic valve 47 was opened the permission liquid flow, the oily flow velocity that imports again in

hydraulic cylinder

25 and 26 was controlled by adjustable throttling 48.

Cross section (Fig. 4) about shaped region 22, can recognize when mould is in complete closing position, tooth bar is kept by four contour forming elements: first forming element is a bottom dentation module 52, the second and the 3rd forming element is that backing (rolling die)

module

53 and 54, the four forming elements are upper modules 55.

Side module

56 and 57 can be made of one with bottom dentation module 52, but makes and operate it is made separate shape for convenient here.

Backing module

53 and 54 is supported by the

pivot block

58 and 59 that remains on the upper mould member 18 respectively.

Described upper modules 55 is mechanically separated (see figure 3) with upper clamp 23, and by plunger/hydraulic cylinder mechanism hydraulic-driven, they not only separate these assemblies respectively in the present embodiment, and independent control.

The motor performance of forming element 52～57 is at United States Patent (USP) 4,571, all describes in 982.The present invention is with the important difference of the United States Patent (USP) 4,571,982 that relates to these different elements operations, is controlled with hydraulic means by the plastic force that upper modules 55 is applied on the tooth bar 20, rather than control with mechanical type spring or spring.This makes action time of the plastic force that applied by upper modules 55 that size and characteristic (non-linear to linearity) are easy to change, so that it can carry out meticulous adjustment apace, easily to be applicable to the tooth bar of different designs scheme.

As previously mentioned, when upper mould member 18 descended, tooth bar 20 was at first by upper clamp 23 and lower clamp 24 clampings.When upper mould member 18 further descended, backing module 53 contacted with tooth bar 20 with 54 beginnings, and at this moment, tooth bar 20 contacts with the top of bottom dentation module 52.On this point in this cycle, according to required degrees of offset between the stylolitic part of the tooth of designed Y type cross section, tooth bar and the tooth bar made and the band toothed portion, upper modules 55 can not contact with tooth bar 20.

Fig. 6,7 and 8 is schematic diagrames of the partially-formed process of Y type of expression tooth bar, so because be symmetry half only is shown.

Fig. 6 shows in lower clamp 24 and arrives the bottom during moment, the relative position of bottom dentation module 52, tooth bar 20, backing module 53 and upper modules 55.At this point place of forming period, the further decline of upper modules 55 relative bottom dentation modules 52 can be because of contact the be obstructed (see figure 3) of plunger 71 with stop block 72 and upper clamp 23.

Upper mould member 18 further descends, and backing module 53 relative bottom dentation modules 52 move down with speed 60, and carry out the backing campaign with rotating shaft 58 (not shown) around its instantaneous centre, and its speed is with velocity component 61 expressions.The resultant motion of backing module 53 is controlled by composite force system, and this power system comprises: normal direction forging force 62 and 64; Friction forging force 63 and 65; Normal force 68 and frictional force 69; The elastic force 66 that leaf spring 135 (Fig. 4) produces; And the normal direction forging force 67 that acts on described upper modules 55.By select

backing module

53 and 54,

pivot block

58 and 59 and the geometry of upper modules 55 make it form a power system, this power system makes the motion excursion of

backing module

53 and 54, so that produce slight contacting (power 68 and 69 value are less) with upper modules 55.As a result, sum velocity vector 70 is represented backing module 53 and the speed of upper modules 55 on contact point, and is basically parallel to the side of upper modules 55 in whole forming process.

Other element shown in Fig. 4 is a pad 118,119,120 and 121, and they are ground into and make basic size be adapted to the tooth bar specification to be formed of each different designs.These pads allow the geometric profile of

backing module

53 and 54 motions to change in certain limit, this can change by the backing module transient motion center separately that changes respectively between

pivot block

58 and 59, and these pads can also compensate with tool processes and module brought up and down

strain.Pad

122 and 32 are set, and the size that is used for compensating after dentation module 52 and upper modules 55 trimmings in vertical direction changes.

Hereinafter will further describe the operating process of shaped region 22.In upper mould member 18 descended, the supply oil pressure of hydraulic cylinder 75 acted on the piston 74, and plunger 73 is stretched out, and contacts with end guard 76, and end guard 76 is clipped between plunger 73 and the stop block 77.This action occur in just

anchor clamps

23 and 24 with tooth bar 20 between contact first before.End guard 76 can rotate around axle 82, remains in whole forming process on this nipped position, so that stop the metal longitudinal of forging the zone to extruding.Extrude longitudinally by

anchor clamps

23,24 clamping actions from the metal of shaped region opposite end and to stop.

When upper mold member 18 continues to descend, when plunger 73 relative upper mould members 18 move up, oil is discharged from hydraulic cylinder 75 by piston 74.The oil of being discharged can not flow to hydraulic cylinder 83, stretches out fully before this because the oil pressure effect of supplying with by magnetic valve 86, adjustable throttling 87 and check valve 88 has been arranged hydraulic cylinder 83 in (piston 84 to bottom offset until contacting with pad 85).The oil of being discharged can not flow back to fuel tank 91 under the effect of overflow valve 89, can not flow back to pump 92 under the effect of check valve 88.Therefore the oil of being discharged at first is discharged to overflow valve 29 from the mouth 93 of guiding valve (spool valve) 138.The whole shift positions that please note this spool 94 shown in Fig. 3 and Figure 10 (c), beginning, spool 94 under the spring between the collar 96 and the housing 97 95 effect fully to bottom offset (seeing Fig. 3 and 10 (a)).Part when Figure 10 (b) shows spool 94 through its stroke is communicated with.The collar 96 is used in masterpiece on the pin 98.Pin 98 is given spool 94 with its load transfer.When spool (valve spool) 94 was in extreme lower position fully, mouth 93 was opened, and is communicated with chamber 99.

Therefore, when piston 74 moved, the initial pressure that acts on

hydraulic cylinder

75 and 83 was (to be generally 2～3.5MPa) by the system pressure that overflow valve 29 is determined.

Along with upper mould member 18 continues to descend, spool 94 relative guiding valve multitube bodies (manifold) 90 move up, gradually with the be communicated with cut-out of chamber 99 with outlet 93.The direction-sense variation of angle that guiding valve acts on the flat part 100 that outlet 93 area processed with cylindric spool 94 sides changes.This point is by realizing around axis 101 slewing circle column housings 97.The pin 102 of spool 94 cooperates with groove 137 in the housing 97, and housing 97 and spool 94 are linked together, and therefore, the rotation of housing 97 passes to spool 94 together rotates it.In this way, all or part of of flat part 100 appears on the mouth 93, thinks that guiding valve provides desirable a changed area performance.With 10 (d), 10 (e) and 10 (f) is profile with the E-E plane of 10 (a), 10 (b) and 10 (c), the plan view of the different angles orientation of the flat part 100 of expression phase counterpart 93.

The mould period of contact, pad 103 joins by hammer (striker) 104 and lower die member 19.Spool 94 moves up by contacting with pad 103, and by the thickness that changes pad 103, when mould was closed, the pressure change procedure in the

hydraulic cylinder

75 and 83 can be from the forming period of different phase according to designed tooth bar.As previously mentioned, the orientation of the flat part 100 that the speed that increases of mould period of contact pressure can be by changing phase counterpart 93 changes.

Engrave when a certain fixed point of forming period, 2～3mm before the complete closure of mould for example, spool 94 cut off and mouthful 93 be communicated with fully.The fluid of any further discharge must be discharged from overflow valve 89, and the structure of described valve 89 and operating principle are similar to aforementioned overflow valve 30.In case when reaching the discharge pressure of being set up by overflow valve 89, oil just through port 105 is discharged to overflow valve 29 and enters in the fuel tank 91.The accumulator 107 that is provided with is the same with accumulator 44, and pressure rising speed is limited on the acceptable value.

Accumulator 108 is bladder type hydropneumatic accumulators of inflating in advance, this accumulator 108 is set is in order to receive from the oil (typical flow is 600l/min) of mouth 93 is discharged moment high flow rate.Gas that

accumulator

44 and 107 does not charge into or air bag are isolated, but rely on the compressibility effect of oil to limit the pressure rising speed that acts on

overflow valve

30 and 89 respectively.

Move upward by spool 94, the oil of discharging from hydraulic cylinder 113 115 and 117 is discharged in the chamber 116 by holing, and is then discharged by mouth 114.

Other Hydraulic Elements as shown in Figure 3 comprise: suction filter 109, oil tank ventilating device 110, oil cooler 111 and safety check valve 112, under something unexpected happened, be that magnetic valve 86 is opened, oil circuit is connected, the all hydraulic cylinder stretch out fully and spool 94 when its extreme higher position (such as the closure of mould during setting, or spool is stuck), safety check valve 112 is set also can provides a stream, to close flowing from mouth 93.If there is not safety check valve 112, pump 92 can stall and overheated fast.In normal operation, safety check valve 112 there is no need.

The size of final die pressure and the perfect shaping degree and the dentine amount key that give tooth bar by bottom dentation module 52 usually brought thus depend on the maximum (see figure 8) that power 67 is obtained.According to United States Patent (USP) the 4th, 571, in the mould that the 982 existing technology that provided are produced, this power is to be controlled by foregoing mechanical spring, in view of actual conditions, can utilize beam type spring (per unit volume can store high-energy), (be typically 2～4mm) because the impulse stroke of beam type spring is relatively short, and final load height (to 50～60 tons of each carryings of a pair of identical spring), these springs have higher preload.Though from the viewpoint of fatigue life of these springs is useful, but this high preload does not have any necessity to upper modules 55, because upper modules 55 only just reaches power 67 at full capacity when 1～2mm of the last closure of mould, but viewpoint from

chucking operation

23 and 24, wish again so, because must produce big chucking power at the early stage of the cycle of forging.Generally speaking, in this inharmonious and Y pattern tool technology formerly between mould (after contact at the beginning, just needing to set up as early as possible bigger chucking power) clamping zone 21 and shaped region 22 demand of (upper modules 55 and plunger 73 need lower starting force) to act on starting force on the forming element in clamping zone 21 and the shaped region 22 respectively, finally the not malleable of the rate of change of power and power all is that the embodiment of the invention overcomes.

To 9 (e), clamping and shaped region 21 and the power of 22 required Hydraulic Elements and the basic difference between the cylinder pressure characteristic are made qualitative explanation respectively with reference to Fig. 9 (a).

Fig. 9 (a)～(e) abscissa is represented each routine aperture δ between top cross member 18 and the lower die member 19.δ=0 o'clock represents that mould is closed fully, shown in Fig. 3,4 and 5.Value δ=-10 expression upper mould members 18 still have the stroke of 10mm apart from complete closed attitude, and have opened 10mm after value δ=+ 10 expression upper mould members 18 complete closed attitudes.

Among Fig. 9 (a)～(e), process (i)～(iv) be defined as follows:

(i) the contact moment between expression plunger 23 and the end guard 76;

(ii) represent to contact for the first time between upper clamp 23 and the tooth bar base 20 moment;

The bottom of (iii) representing anchor clamps 24 bottom position contact with pad 31 moment and;

(iv) represent mould fully closed (δ=0) moment.

Power F among Fig. 9 (a) ₂₃And F ₂₄Be respectively that upper clamp 23 and lower clamp 24 are applied to the power on the tooth bar 20.Among Fig. 9 (b), power F ₅₅Be that upper modules 55 is applied to the power on the tooth bar 20, power F ₇₃Be that plunger 73 is applied to the power on the end guard 76.Among Fig. 9 (c), pressure P ₂₅And P ₂₆Represent

hydraulic cylinder

25 and 26 pressure that produce respectively.Among Fig. 9 (d), pressure P ₇₅And P ₈₃Represent

hydraulic cylinder

75 and 83 pressure that produce respectively, " t " expression time among Fig. 9 (e).

Between upper clamp 23 and tooth bar 20, contact moment (ii) for the first time, act on the power F of upper clamp 23 and lower clamp 24 respectively ₂₃And F ₂₄Be increased to fast as putting 128 and 129 represented values.Put the power F that is obtained at these ₂₃And F ₂₄Value depend on that setting to overflow valve 30, the pressure rising speed in the

hydraulic cylinder

25 and 26 then depend on the oil capacity in the accumulator 44 and the elastic characteristic of accumulator 44.

Be used to shear the power F of tooth bar between the required additional force usefulness point 128 and 129,127 and 126 of the side-play amount at 43 places, plane ₂₃With F ₂₄Difference represent.Shown in Fig. 9 (a), in moment (iii) the time, the bottom of anchor clamps 23 contacts chucking power F at bottommost with pad 31 ₂₃And F ₂₄Increase.Power F ₂₃With F ₂₄Difference moment (iii) and mould closed to greatest extent moment keep constant (iv) substantially between (δ=0).Although pressure P ₂₅And P ₂₆(iii) keep to equate and be constant in the back in moment, still, because of the area of piston 36 area, and begin to move with respect to upper mould member 18 (iii) the time, so chucking power F in moment greater than piston 28 ₂₃And F ₂₄Increase.Moment (iii) before, act on the pressure P on the piston 36 ₂₅Partial action is on pad 35, and partial action is in upper clamp 23.Moment (iii) after, act on the whole pressure P on the piston 36 ₂₅Value is delivered on the upper clamp 23, increases chucking power F thus ₂₃And F ₂₄

In moment (iii) and (iv), chucking power F ₂₃And F ₂₄Difference be shearing force on the tooth bar 20 in the plane 43, and, bottom chucking power F ₂₄Value added, partial action is on pad 31, part is passed through pressure P ₂₆Act on the piston 28.

It should be noted that according to the present invention, by regulating overflow valve 30 realizable force F at an easy rate ₂₃And F ₂₄Value change, make it reach desired value, extrude from anchor clamps 23 and 24 to avoid the metal in shaped region 21.

At the moment (δ=0) that mould is opened, chucking power F ₂₃And F ₂₄Reduce to 1 (point 131) at once.Then, by the clamping action of

backing module

53 and 54 on Y type bar 14, the tooth bar 20 that is shaped is extracted out from dentation module 52.This clamping action is produced by the power 66 that the spring steel making sheet spring 135 and 136 that is contained in

backing module

53 and 54 applies respectively.

It should be noted that after the moment (δ=0) that mould is opened power F ₅₅And F ₇₃, cylinder pressure P ₂₅, P ₂₆, P ₇₅And P ₈₃All reduce to zero at once rapidly.This means that shaping tooth bar 20 is the tendency from ejecting between

backing module

53 and 54 not, and before magnetic valve 86 was hydraulic cylinder 83 supply oil pressure again, tooth bar 20 was keeping being clamped in the described state that rolls between

module

53 and 54 always.The startup of magnetic valve 86 in the manual loading mould, is handled by operator's activation button, and in having the mould of full-automatic loading system, is automatically handled by control system.

Then when forging (δ＞0), magnetic valve 47 cuts out the cut-out liquid flow, open up to magnetic valve 86 and make liquid flow, and upper modules 55 ejects tooth bar 20.After this, magnetic valve 47 is opened and is made liquid flow, and by acting on the supply oil pressure of

piston

36 and 28 respectively,

hydraulic cylinder

25 and 26 makes upper and lower anchor clamps 23 and 24 stretch out respectively.The speed of stretching out of anchor clamps 23,24 is set by adjustable throttling 48.

In fact, after the shaping, chucking power F ₂₃And F ₂₄Reduce to zero rapidly, guaranteed the mould of the glacing flatness of the tooth bar 20 in this mould, produced significantly better than prior art.

Fig. 9 (e) and 9 (d) have represented the roughly difference of the pressure characteristic that the element of clamping zone 21 and shaped region 22 is required respectively.

Fig. 9 (d) illustrates P ₇₅And P ₈₃Beginning when moment (i) increases.As described above, piston 74 is pistons that first moves in the forming period.Being closed to last 2-3mm at mould just need make and act on the end guard 76 chucking power and reach maximum, therefore, the speed that the commitment pressure of mould closure raises is very fast at first, reason is that the flow velocity of oil progressively changes, but the restriction that contracted by the oil pressure in the accumulator 107, then, along with mouth 93 is set up unrestricted relatively oil flow and slack-off, afterwards, pressure is pressed index law to be increased, till pressure reaches a little 132 indicating values, pressure this time, spool 94 cuts off flowing of mouth 93 fully, and overflow valve 89 is opened.Chain-dotted line among Fig. 9 (d) is represented the curve 133 of the another kind of curve form that pressure rising speed combines with the overflow valve set point pressure, and this shows is not needing can to change curve form at an easy rate under the situation of ending the work of mould or processing any element.Power F among Fig. 9 (b) ₅₅And F ₇₃Correspond respectively to the pressure P of Fig. 9 (d) ₈₃And P ₇₅Because the area of piston 74 is less than the area of piston 84, so chucking power F ₇₃Less.Usually, hydraulic cylinder 75 and 83 design peak pressure are at 32～42MPa, and its power is respectively 10～14 tons and 80～110 tons.

By contrast, (ii) begin the pressure P that increases in moment ₂₅And P ₂₆Must increase to the maximum shown in the point 134 of Fig. 9 (c) very soon, to be in before side-play amount in the plane 43 and the basic beginning that is shaped of Y type part clamping tooth bar 20 securely in shearing.As previously mentioned, the speed that pressure raises is subjected to the restriction of accumulator 44, and overflow valve 30 has limited the operating pressure P that acts on respectively on

piston

36 and 28 ₂₅And P ₂₆

At last, Fig. 9 (e) expression is according to two kinds of typical time-displacement curves of mould of the present invention.The curve of solid line and dotted line is represented the typical typical value of fly press and crank press respectively.Note that for fly press the time of contact between tooth bar and the forming element is shorter, be of value to producing in enormous quantities and use,, increased time of contact though use crank press, but can not cause reduce significantly life tools, so, also can adopt crank press.

Should be appreciated that for those skilled in the art, in the spirit and scope that do not break away from claim of the present invention and limited, can make multiple change and distortion.

Claims

1. mould, make blank be processed into steering rack band toothed portion with this mould by forging, this band toothed portion has the spigot surface of toothed and at least two longitudinal extensions, described mould comprises first, second die component and by first, second, the element group that the 3rd and the 4th forming element is formed, these forming elements can be gathered on blank when blank is put into mould with relatively moving, first forming element is the part of second die component, and one of them mask has and the corresponding shape of described profile of tooth, the second and the 3rd forming element is the part of first die component, and has a forming face of the spigot surface that is suitable for processing belt toothed portion longitudinal extension, the 4th forming element links to each other with first biasing device, can slide with respect to first die component between the second and the 3rd forming element, and be suitable for the processing belt toothed portion between two spigot surfaces and with the tooth facing surfaces, described first biasing device allows the 4th forming element to leave blank during forging under the load effect and moves, this mould also is included in during the forging the vertically clamping device of restriction blank, clamping device is included in the first and second relative anchor clamps that the non-machined surface of blank applied during the forging radial load, first anchor clamps link to each other with second biasing device, and can slide by relative first die component, second anchor clamps link to each other with the 3rd biasing device, and can slide by relative second die component, it is characterized in that first biasing device mechanically separates with second biasing device.

2. mould according to claim 1 is characterized in that, first biasing device and second biasing device are hydraulic actuators.

3. mould according to claim 1 is characterized in that the 3rd biasing device is a hydraulic actuator.

4. mould according to claim 1 is characterized in that, the second and the 3rd biasing device is a hydraulic actuator, and mutual fluid connection.

5. mould according to claim 1 is characterized in that, at least two of first, second and the 3rd biasing device is hydraulic actuator, and the pressure effect moment at least one hydraulic actuator and size are to control separately.

6. mould according to claim 1, it is characterized in that, described mould also comprises the restraint device that is used for vertically limiting blank during forging, this restraint device is being rotatably mounted around the axis that is basically perpendicular to the blank longitudinal axis, and has a surface that is basically perpendicular to the blank longitudinal axis, and, be clamped in by a clamping device on the fixed stop part of second die component at the mould period of contact.

7. mould according to claim 1, it is characterized in that, at least one is a hydraulic actuator in first, second or the 3rd biasing device, wherein the pressure that is fed in this hydraulic actuator is controlled, and makes it become the function that first and second die components relatively move.

8. mould according to claim 1 is characterized in that, at least one of first, second and the 3rd biasing device is the hydraulic actuator by at least one Pressure relief valve control.

9. mould according to claim 1, it is characterized in that, at least one of first, second and the 3rd biasing device is hydraulic actuator, and this actuator is controlled by at least one Pressure relief valve, and at least one accumulator is connected on the hydraulic connecting device between hydraulic actuator and the overflow valve.

10. mould, make blank be processed into steering rack band toothed portion with this mould by forging, this band toothed portion has the spigot surface of toothed and at least two longitudinal extensions, described mould comprises first, second die component and by first, second, the element group that the 3rd and the 4th forming element is formed, these forming elements can relatively move when blank is put into mould and gather on blank, first forming element is the part of second die component, and one of them mask has and the corresponding shape of described profile of tooth, the second and the 3rd forming element is the part of first die component, and has a face of the spigot surface that is suitable for processing belt toothed portion longitudinal extension, the 4th forming element links to each other with first hydraulic actuator, can between the second and the 3rd forming element, slide with respect to first die component, and be suitable for the processing belt toothed portion between two spigot surfaces and with the tooth facing surfaces, first hydraulic actuator allows the 4th forming element to move down the cogging material and move in the load effect during forging, it is characterized in that, pressure effect moment and size in first hydraulic actuator are controlled.